This application claims the priority of German Application No. 199 02 635.1, filed in Germany on Jan. 23, 1999, and PCT Application No. PCT/EP99/09013, filed on Nov. 23, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a method according to the preamble of the first claim and an apparatus for the practice of the method according to the preamble of the fourth claim.
In the assembly of motor vehicles, a number of methods are known for fitting the side doors as accurately as possible with little need for readjustment operations.
In the present case, only those methods are of interest which deal with vehicle doors that are bolted on. In this case it is required that the surfaces of the hinges that are fitted to mating surfaces on the vehicle body be flat against one another without gaps. If hinges are to be welded on, this is unnecessary, and gaps can be present between the hinges and the contact surfaces on the vehicle body. Such gaps are caused by tolerances between the body and the door. The strength of the welds makes these gaps, up to a certain width, tolerable.
A method for bolting a vehicle door to a vehicle body is disclosed in DE 33 42 570 C. Here the prepared door is fitted by an industrial robot into a corresponding door opening. The fitting is performed by sensing fingers and gauges by means of a computer which determines the position of the door. Also, a special three-part hinge must be used in order then to be able to bolt in place the precisely aligned door.
Methods using sensing heads and computers, as well as robots, to hold the door while it is being bolted have proven practical only conditionally, since many inaccuracies can occur and very complex computer programs are necessary.
The problem of the present invention is to improve the above-mentioned method and optimize it for use on an assembly line. It is also the problem of the invention to propose a suitable apparatus for the purpose.
As to its procedural aspects the invention is solved by the features of the first claim, and as to the apparatus involved it is solved by the features of the fourth claim.
The solution is based on the knowledge that the alignment of the vehicle door is performed mechanically, without the need for a computer or industrial robot to fit the door in place. A robot can be used only to transport the door from where it is prepared to the door frame. But the robot does not have the need to align the door and then also hold it in place.
With the bolting procedure proposed by the invention the alignment of the door in the door opening can be achieved with simple means, the method being applicable preferably to a vehicle body with at least four doors, since it can be assured by the method of the invention that both doors are flush with one side of the vehicle. This flush fitting is achieved according to claim 3 by using the same alignment points for the front and rear door of one side of the car in the area of the B post.
The solution according to claim 4 has the advantage that it is accomplished with purely mechanical components for aligning and holding the door in position in the door opening.
Subordinate claims 5 to 14 describe preferred embodiments of the apparatus of claim 4, stressing that both the door frame on the car body and the individual beams for the car doors can be aligned free of tensions. Care has been taken to see that three docking points establish the mounting frame and the individual beams on the width of the car (direction Y), two docking points on the height of the car (direction Z) and one point on the length of the car (direction X).
Another advantage of the invention is to be seen in the fact that ordinary screw-mounting hinges can be used as long as it is assured that the mating surfaces and thus the leaves of the hinges are approximately perpendicular to one another when the door is closed. The bolting itself can then be performed manually or by bolting robots. This, however, is familiar and therefore is not further described.
The invention is described below in conjunction with a preferred embodiment.